Agglomerated porous mass and method of preparing same

ABSTRACT

The method of recovering oil leakage from the surface of a body of water, comprising the steps of mixing discrete core particles of wood material, polyethylene and finely ground coal to form particles having a high affinity for oil. The particles have a high degree of integrity, thereby permitting storage of the same at points relatively remote from the point of leakage and airlifting of the same to the oil spot. The oil-saturated particles are processed after collection for further use as a fuel source, with the B.t.u. content being as great or greater than bituminous coal.

United States Patent Bunn [4 1 *Mar. 28, 1972 [54] AGGLOMERATED POROUSMASS AND [56] References Cited METHOD OF PREPARING SAME UNITED STATESPATENTS 72 I 1: Clint 0.13 ,D ,Cl. 1 3,382,170 5/1968 Pape ..2i0/36 [73]Assignee: Col-Mont Corporation, Butte, Mont. 3,536,615 10/1970 Bunn...;..2l0/4O X e 1 Notice: The portion of the term of this patent subpn-maryExaminer Reuben Friedman sequcm Oct 27, 1987, has been AssistamExaminer-Thomas G. Wyse clalmed- Auamey0berlin, Maky, Donnelly andRenner l [22] Filed Ju y 1, 1970 ABSTRACT [2]] App! NOT SL541 The methodof recovering oil leakage from the surface of a body of water,comprising the steps of mixing discrete core 52 U.S.CI ..210/s02,l17/148,2l0/36, P of Wood material, Polyethylene and finely smund coalto form articles having a hi h affinit for oil. The parti- 2i0/DIG.21 lh P t t 5 1 1 Int. Cl. ..B0ld 39/04, C02b 9/02 gf g f i: f:; i gi [58]Field of Search .,....210/36, 40, DIG. 21, 502, 504, leakage andairlifiing of the Sam: to the on SPOL The oibsanb 210/506; 1 17/72 149rated particles are processed after collection for further use as a fuelsource, with the B.t.u. content being as great or greater thanbituminous coal.

10 Claims, 1 Drawing Figure POLYETHYLENE wooo PARTlCLES IN 30 I2 l4SOLVENT OR IO PARAFFIN AS I REQU'RED HEAT HEAT 28 i 8 MIX AT 0 l8 ST lMIXER I l PRODUCT Ill! 5I PREHEAT REHEAT COOL 2O 22 i6 24 2e PATENTED MR2 8 I972 INVENTOR CLINTON O. BUNN 8 v mm ZwIwE I 22.6mm! www z 1 23 .DOP0300: a

Z kmDo 300 Z mmJofrmza 0003 "@m TORNE YS AGGLOMERATED POROUS MASS ANDMETHOD OF PREPARING SAME BACKGROUND OF THE INVENTION The presentinvention relates as indicated to a method of and apparatus forrecovering oil from the surface of water. Although applicable toessentially any situation where oil is present on the surface of thewater and is desired to be removed therefrom, it is particularly wellsuited to large scale oil recovery where leakage has resulted from thedisability of or damage to large vessels such as oil tankers, or wherethe leakage has resulted from offshore drilling operations. This lattersituation in particular has posed a vexing problem to the industry whichthus far has not been satisfactorily solved.

The problem of oil leakage and a proposed solution was disclosed in myearlier application, Ser. No. 848,039, filed Aug. 6, 1969, and entitledMETHOD OF AND APPARATUS FOR TREATING OIL LEAKAGE, now U.S. Pat. No.3,536,615 dated Oct. 27, I970. The present application comprises animprovement over my earlier application in that I have discovered thatcertain materials disclosed in my earlier application are more effectivefor the purpose intended, and other forms of apparatus have proved to beequally successful in the formation of the oil-collecting particles,which particles have a high affinity for oil and are adapted to bespread on the surface of the water for selectively collecting the oil.

SUMMARY OF THE INVENTION A primary object of the present invention is toprovide a method of and apparatus for recovering oil from the surface ofwater wherein three low cost ingredients are provided for forming theoil-absorbing particles, namely, wood, carbon and a combustibleadhesive, with polyethylene presently being the economically preferredmaterial. The wood may be present in essentially any size or form, butis preferably in the form of relatively small chips in the range of upto /2 inch in size, with A inch being most preferable. Sawdust is alsofeasible in accordance with an alternative form of the invention. Thepolyethylene adhesive is preferably of the readily available, lowdensity type, and the carbon is preferably present in the form of finelyground coal, another material found greatly in abundance in manyportions of the country. Absolutely essential in the combination ofthese ingredients is the formation of particles which have a specificgravity initially less than one and which have a relatively porous opencellular structure. Such structure increases the coal surface contactarea thereby providing maximum oil adsorption per unit weight ofmaterial.

A further important object of the present invention is to provide such amethod of recovering oil wherein the oil affinitive particles arecomprised not only of low cost materials, but materials which at thepresent time comprise pollutants to our environment. The wood materialis formed from or comprises essentially waste material, with sawdustbeing satisfactory in the practice of the invention. The polyethyleneemployed is finely ground, cut or chopped to the desired size, and canbe obtained from processing what are essentially single use materials,which must be otherwise disposed of in increasing quantities in oursolid refuse disposal operations, the problems of which are plaguingmunicipalities everywhere. The third ingredient, coal dust, is presentlyconsidered an irritating, dangerous by-product of coal production. Acommon method of ridding the mines of coal dust, particularly withnon-coking coal, is to dilute the same in lime dust underground so as toreduce the danger of fire. The beneficial use of coal dust in accordancewith the present invention is thus of important significance to the coalindustry.

A further object of the present invention is to provide such a methodand apparatus wherein the product obtained is not significantly affectedeither by the sequence of addition of ingredients or by the need forcritically small percentage ranges of each ingredient, within the abovementioned parameters of specific gravity and surface area.

A further object of the present invention is to provide a method of andapparatus for recovering oil wherein the oil collection particlespossess a relatively high degree of integrity. This not only permitsstorage of the particles for relatively long periods of time prior touse, but enables the particles to retain their physical characteristicsand oil-absorptive capabilities when subjected both to violent agitationover long periods during use, and subsequently following absorption.Such particle integrity also permits the material to be transported tothe site where needed without adversely affecting the collectionprocess. It is therefore envisioned that the oil collecting particlescould be stored at relatively remote site locations and flown, in thequantities needed, to the location of the oil. Particle integrity isalso important in the handling of the oil-laden particles aftercollection in order to avoid disintegration.

A further object of the present invention is to provide a method of andapparatus for recovering oil wherein the particles may possess apredetermined water absorption rate over time when in continued contactwith water. In accordance with the invention, the constituents of theparticles have been selected and proportioned to provide a mixture whichis initially lighter than water. Subsequent and continued contact withwater will increase the density of the float particle due to theabsorption of water by the portion of the wood chip which is not coatedwith the polyethylene. After the float particle absorbs a predeterminedweight of water, the lighter than water particle becomes heavier thanwater. In this manner any of the oil-absorbing float particles which arenot recovered during the collecting operation of the system willeventually sink to the bottom so as to eliminate the particles frombeing themselves a future pollution problem. The principal purpose of myinvention, which is removal of polluting oil from the surface of thewater, has therefore been served, in spite of the nonrecovery of thefloat particle.

A still further object of the present invention is to provide a methodof and apparatus for recovering oil wherein the particles, following theoil recovery process, can be treated further for use as a convenient andeconomical fuel source. The constituents of the particles have beenselected to provide the desired fuel properties, with the particles whenadsorbed/absorbed with oil having a heat value as great or greater thanbituminous coal. It should be noted that the words adsorbed" 'andabsorbed" are used synonymously herein. The degree of adsorption orabsorption of the oil by the particles varies significantly depending onmany factors, including the percentage of the respective ingredients,the time of exposure of the particle to the oil and water, etc.Accordingly, although the description hereinafter will be primarilylimited to the term adsorbed it will be understood that the concepts ofthe invention envision absorption as well, either sequentially due totime considerations or simultaneously owing to the particular makeup ofthe oil collecting particles.

These and other objects of the invention will be apparent as thedescription proceeds in particular reference to the attached drawing, inwhich:

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a schematic view of thepreferred process of making the oil affinitive, coated particles.

DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown in the drawingapparatus by means of which the preferred method of the presentinvention can be accomplished. The apparatus has been shownschematically inasmuch as no invention resides in the specific parts orcomponents of the apparatus employed, but only in the overall use towhich the apparatus is put. All parts of the apparatus are commerciallyavailable items, as will be pointed out hereinbelow when the method isspecifically described.

As previously mentioned, applicants novel method comprises the mixing ofthree basic ingredients, wood,

polyethylene, and coal. These ingredients may be mixed in any suitablemixing apparatus which functions to intimately mix the coal andpolyethylene. It is not essential that the entire surface of the woodparticles be covered, although the polyethylene additionally functionsas a sealant and to the extent that the surface of the wood is notsealed, the wood will indiscriminately adsorb water as well as oil,which may lead to undesired sinking of the particles without fulfillingtheir intended function of oil collection. The complete sealing of thewood will preclude the adsorption of water thereby insuring theselective oil collection by the particles.

In the application drawing, the inlets for the materials have beengenerally indicated at l0, l2 and 114, respectively. The materials arefed through the inlets to a mixer generally indicated at 16, which maycomprise a series of longitudinally spaced and connected mixing devicesof commercially available construction. Various types of mixers are nowavailable for intimately mixing essentially any flowable solids, liquidsor gases, with one such mixture being sold by Kenics Corporation,Danvers, Massachusetts, and sold under the trademark STATIC MlXER. Thismixer is disclosed and claimed in U.S. Pat. No. 3,286,992, and referenceis specifically made thereto for a full understanding of the structureand function of the mixing device. Briefly, the device is provided onthe interior thereof with a plurality of curved blades or elements, eachof which affects the reversal of the flow from the immediately precedingelement whereby the feed material is constantly being divided andintimately mixed with the other-materials fed into the mixer.

The material is forced through the mixer by means of a blower generallyindicated at 38 mounted at the forward end of the apparatus adjacent theinlet 10. Disposed circumferentially around the mixer 16 inlongitudinally spaced relation are heat exchangers indicated at 29, 22,24 and 26. These exchangers are provided for the purpose of eitherheating or cooling the material as it longitudinally passes through theinterior of the mixer. For example, heat exchanger 20 initially heatsthe wood particles as they enter the mixer, and preheat exchanger 22further heats the material. The heat exchanger 24 comprises a reheaterwhich serves to elevate the temperature of the wood and polyethylenemixture, with the polyethylene being fed to the mixer immediatelypreceding the reheater 24. The exchanger 26 comprises a cooler-heatexchanger which serves to cool the entire mixture after the coal hasbeen introduced into the mixer through the inlet 14. The product comingout of the mixer is preferably at a temperature sufficiently low topermit normal handling thereof. For purposes of efficient heatutilization, the heat resulting from the heat transfer at heat exchanger26 may be used as the heat source for the heat exchanger 20.

The wood particles entering the mixer through inlet can be obtained fromany suitable available source of material, and are preferably convertedinto chips approximately onefourth inch in size. From an economicstandpoint, chips of this size can be manufactured completely from wastewood materials such as bark, edgings, rough trim, cull lumber, chippableresidues, and the like. It will be understood that wood in the form ofchips in excess of 54. inch are also satisfactory, as well as wood insmaller size forms. In fact, sawdust can be satisfactorily employed inaccordance with the present invention. If desired, the wood material maybe treated before introduction into the mixer through inlet 10. Forexample, the wood may be coated with a sealant which may comprise thematerials noted in my earlier application such as, for example,shellacs, polyester and furan resins, natural resins, asphalticmaterials, in addition to other well known sealants such as silicones.

The polyethylene is fed into the mixer through inlet 12 after the woodhas been introduced and preheated. The polyethylene is preferably of lowgrade, low density and low molecular weight, and can even comprisereground material for reasons of economy. The material when fed into themixer is preferably in solid, ground form and can be supplied by air tothe interior of the mixer. The polyethylene is preferably preheatedprior to entry into the mixing chamber for the purpose of elevating thetemperature thereof to approximately the temperature of the woodparticles thereby reducing the heating requirements for the main chamberitself.

The viscosity of the polyethylene can be varied substantially by varyingthe feed temperature thereof or through the addition of solvents theretothrough a solvent feedline 30. Solvents suitable for this purposeinclude, xylene, toluene, paraffin or similar known solvents andthinners. At C polyethylene is miscible in organic solvents such astoluene and xylene, and the fluid condition of the polyethylene andsolvent carrier facilitates the mixing operation, as well as permittingreduction of the temperature at which the coal ,is mixed with thepolyethylene coated wood. The solvent is boiled off at a predeterminedelevated temperature.

in addition, although not shown, other materials can be blended withpolyethylene to obtain the desired properties. For example, nylon orpolymers could be blended with the polyethylene to provide permeabilityproperties more compatible with a particular size or type wood feedmaterial. Significantly, any component added to polyethylene shouldpossess essentially the same characteristic of combustibility in orderto provide a product which when collected serves as a useful source offuel.

The polyethylene is intimately mixed in the interior of the mixer withthe wood chips and carried toward the exit end of the mixer, under theinfluence of the blower 18. The mixture of polyethylene and wood chipsis heated by the heat exchanger 24 to approximately C., at whichelevated temperature the adhesive properties of the polyethylene arefully developed in the temperature regions below the char point of thewood, and at this temperature the properties of the coal are notadversely affected. At temperatures much below 160 C., the adhesiveproperties of the polyethylene are not fully developed, and attemperatures in excess of 160 C., the likelihood of combustion of thewood and coal is greatly increased. It will be understood that theoptimum temperature will vary depending upon the type and moisturecontent of the wood, the type, size and moisture content of the coal,the presence of additives to the polyethylene, and the residence time inthe heating chamber.

The coal dust is admitted into the mixer downstream of the reheatexchanger 24. The coal dust can be of substantially any mesh sizealthough superior results are obtained where the coal dust is minusZOO-mesh in size. The quality of the coal can also significantly vary,with sub-bituminous as well as bituminous coal being entirelysatisfactory.

The carbon coated particles are thereafter passed through cooling heatexchanger 26 for further processing.

To summarize the invention thus far described, the wood chips aredelivered to the mixer and heated therein and thereafter coated withground polyethylene admitted to the mixture through the inlet 12. Themixing device greatly enhances the binding of the coal to the woodchips, and predetermined amounts of wood chips and polyethylene aredelivered to the mixer for effectively conditioning the wood particlesprior to passage of the same to the area in the mixer adjacent the coaldust inlet 14. The water absorption rate of the particles can becontrolled by the amount of polyethylene added, with relatively lesseramounts of polyethylene resulting in less than complete sealing of thewood chips, thereby conditioning the particles for absorption of waterand/or oil.

As the polyethylene coated particles pass below the coal dust inlet 14,coal is added to the wood chips in such predetermined arnounts as tobind coal to essentially all the wood particles passing adjacentthereto. As previously stated, the wood chips are heated during thetraversal thereof through the mixer and are preferably at a temperatureat least as high as 160 C. prior to the dusting of the same with thecoal particles.

After the application of the coal dust to the particles, the particlespass through the cooler-heat exchanger 26 for cooling the same andsetting the bond between the wood chips and the coal dust. The particlescan be removed from the mixer in any suitable manner and with knownapparatus. For example, the particles could be collected at the end ofthe mixer and conveyed therefrom to apparatus for further handling ofthe particles.

As above noted, one of the principal advantages of the present inventionis the lack of criticality in the sequence of addition of the materialingredients which form the final, coated product. In lieu of thearrangement as shown in the application drawing wherein polyethylene isapplied to the surface of the wood chips and the resultant coatedparticles thereafter mixed with coal, an alternative method comprisesthe intimate mixing of wood and coal, with the resulting discreteparticles being thereafter mixed with finely ground polyethylene. Thisprocess can be carried out in the same type mixing apparatus illustratedin the application drawing.

In the alternative process, the sawdust and coal are conveyed to themixer 16 illustrated in the application drawing and intimately mixedtherein. The coal is preferably minus ZOO-mesh and can be, as previouslyindicated, sub-bituminous in quality. The sawdust, as contrasted to therelatively larger wood chips, provides for increased permeability,reduced bulk density, and a greater coal/wood ratio. To enhance theintimate mixing of the wood and coal, the former is preferably dampened,for example with water, so as to permit the sawdust to be thoroughlycoated with the finely ground coal and polyethylene.

The coated sawdust is thereafter intimately mixed with finely groundpolyethylene, with the latter preferably covering essentially the entiresurface of the particles. The polyethylene is added in predeterminedamounts to effect such thorough mixing, and highly satisfactory resultshave been achieved where the wood to polyethylene to coal ratio is1:2:3, respectively.

The sawdust thus sequentially coated with coal and polyethylene isthereafter heated at approximately l60 C. until the polyethylene becomesadhesive. The heating step can be effected in a manner similar to thatabove described and illustrated in which the coated particles are passedthrough a heat exchanger for a time sufficient to reach such temperatureand effect the adhesion process. Any suitable source of heat may beemployed. The fused particles or agglomerates are thereafter cooledproviding discrete particles having a great affinity for oil. It will beunderstood that in lieu of the mixing device illustrated, otherapparatus may be employed for mixing and heating the components in bothof the described methods. For example, batch pans, conveyor belts,fluidized beds, twin pug mixers or rotary mixers can be employed toeffeet the mixing and heating. The important consideration is theability of the apparatus employed to mix thoroughly and develop heatquickly so as to effect bonding of the coal to the wood material.

The integrity of the finally treated particles is an importantcharacteristic, permitting the transportation and/or storage of theparticles over long periods of time without significant deterioration ofthe product, provided excessive oxidation of the particles is prevented.

In the actual employment of the particles in the oil recoveringoperation, the particles can be spread over the surface of the water inany suitable manner. Disclosed in my earlier ap plication is the methodof handling comprising the spreading of the particles on the surface ofthe water by means of a spreader ship, with the oil-adsorbed particlesbeing collected by a recovery ship for further processing. This methodcould be used as well in accordance with the present invention, althoughit is contemplated that in view of the integrity of the oil affinitiveparticles, the same can be stored at relatively remote locations andtransported by air to the location where needed. Relatively largeamounts of the product could be airlifted and air scattered on the areaof the water surface bearing the oil. A recovery ship would then bedispatched to the location and the oil-adsorbed particles collected.

On the basis of experimental tests, conducted in accordance with thealternative method just described, approximately three tons of floatmaterial will collect approximately 2 tons of oil. In view of the readyavailability and cheapness of the ingredients comprising the oilaffinitive particles of the present invention, it will be seen that theoil can be recovered very economically. It should also be kept in mindthat, unlike previous oil recovery methods and materials, the presentmethod makes use of the collected particles as a readily availablesource of fuel. In this regard, further treatment of the particles isnormally desirable and may, for example, comprise, as disclosed in myearlier application, drying and/or compacting of the particles intobriquet shaped sizes for more convenient handling and storing. It willbe apparent that the oil can be recovered, as an alternative treatment,by flask distillation.

In regard to the fuel value of the particles both before and after theoil recovery process, testing has shown that the B.t.u. content of theparticles before the oil adsorption is approximately 14,200 B.t.u. perpound, approximately the value of bituminous coal, and the fuel valueafter adsorption is approximately 18,000 B.t.u. per pound. All of thedisclosed ingredients add to the fuel value of the product, and it willbe understood that the fuel value will vary significantly with theseparate heating values of the wood and coal employed in the formationof the oil affinitive particles.

I, therefore, particularly point out and distinctly claim as myinvention:

1. The method of preparing an agglomerated porous mass, comprising thesteps of:

1. providing discrete core particles of light weight material, suchmaterial being combustible and sufficiently light to float on water,

2. heating said core particles,

3. applying to the surface of said heated particles polyethylene andpowdered coal, and

4. heating said coated particles to a temperature sufficiently high tomelt said polyethylene but below the burning point of said core materialand said powdered coal, said polyethylene serving as an agglomeratingand bonding agent and causing the bonding of said coal to said coreparticles thereby to form an agglomerated porous mass light in weightand combustible, and having a high affinity for oil.

2. The method of claim 1 wherein said discrete core particles of lightweight material are wood.

3. The method of claim 2 wherein said wood particles are in the form ofwood chips approximately 841 inch in size.

4. The method of claim 1 wherein said powdered coal is minus ZOO-mesh orsmaller in size.

5. The method of claim 1 wherein the temperature at which saidpolyethylene bonds said coal to said core particles is approximately C.

6. The method of claim 1 further including the steps of spreading theagglomerated porous material on the surface of the water to absorb theoil, collecting the oil adsorbed particles from the surface of thewater, and treating the collected particles for rendering the samesubstantially immediately useable as a fuel source.

7. The method of claim 1 wherein said core particles and saidpolyethylene and said coal are independently fed into and conveyedthrough a confined housing, and intimately mixed therein.

8. The method of preparing an agglomerated porous mass, comprising thesteps of: v

1. providing discrete core particles of light weight material, suchmaterial being combustible and sufficiently light to float on water,

2. passing said particles by induced air in a continuous path through aconfined housing,

3. heating said particles while said particles are passed through saidhousing,

4. applying to said heated core particles polyethylene as anagglomerating and bonding agent,

5. heating said polyethylene to a temperature of approximately l60 C.and

7 8 6. applying powdered coal to the polyethylene-coated corepolyethylene,

particles causing the agglomeration of the particles into a 4. heatingsaid particles at approximately 160 C. until said porous matrix, saidparticles as thus agglomerated with polyethylene melts and fuses withsaid carbonaceous coal being light in weight and combustible, and havinga material Coating ai fibrous materialand high affinity for oil. 5.cooling said fused particles thereby to provide discrete 9. The methodof preparing an agglomerated porous mass, agglomerates which B in Weigh!$0 85 n08! comprising the steps of: water, combustible, andcharacterized by a high affinity 1. providing discrete core particles oflight weight fibrous material, such material being combustible andsufficiently 9- 8 8 R ous mass 8 ""8 f havinS light to t on water, ahigh afiinity for 011, said mass comprising a plurality of discrete coreparticles of fibrous material, and powdered coal bonded to said discretecore particles by fused polyethylene.

* I. III 1F t 2. thoroughly mixing said fibrous particles with finelyground carbonaceous material, 3. mixing said coated fibrous particleswith finely ground

2. The method of claim 1 wherein said discrete core particles of lightweight material are wood.
 2. passing said particles by induced air in acontinuous path through a confined housing,
 2. thoroughly mixing saidfibrous particles with finely ground carbonaceous material,
 2. heatingsaid core particles,
 3. applying to the surface of said heated particlespolyethylene and powdered coal, and
 3. mixing said coated fibrousparticles with finely ground polyethylene,
 3. heating said particleswhile said particles are passed through said housing,
 3. The method ofclaim 2 wherein said wood particles are in the form of wood chipsapproximately 1/4 inch in size.
 4. The method of claim 1 wherein saidpowdered coal is minus 200-mesh or smaller in size.
 4. applying to saidheated core particles polyethylene as an agglomerating and bondingagent,
 4. heating said particles at approximately 160* C. until saidpolyethylene melts and fuses with said carbonaceous material coatingsaid fibrous material, and
 4. heating said coated particles to atemperature sufficiently high to melt said polyethylene but below theburning point of said core material and said powdered coal, saidpolyethylene serving as an agglomerating and bonding agent and causingthe bonding of said coal to said core particles thereby to form anagglomerated porous mass light in weight and combustible, and having ahigh affinity for oil.
 5. cooling said fused particles thereby toprovide discrete agglomerates which are light in weight so as to floaton water, combustible, and characterized by a high affinity for oil. 5.heating said polyethylene to a temperature of approximately 160* C., and5. The method of claim 1 wherein the temperature at which saidpolyethylene bonds said coal to said core particles is approximately160* C.
 6. The method of claim 1 further including the steps ofspreading the agglomerated porous material on the surface of the waterto absorb the oil, collecting the oil adsorbed particles from thesurface of the water, and treating the collected particles for renderingthe same substantially immediately useable as a fuel source.
 6. applyingpowdered coal to the polyethylene-coated core particles causing theagglomeration of the particles into a porous matrix, said particles asthus agglomerated with coal being light in weight and combustible, andhaving a high affinity for oil.
 7. The method of claim 1 wherein saidcore particles and said polyethylene and said coal are independently fedinto and conveyed through a confined housing, and intimately mixedtherein.
 8. The method of preparing an agglomerated porous mass,comprising the steps of:
 9. The method of preparing an agglomeratedporous mass, comprising the steps of:
 10. An agglomerated porous masslight in weight and having a high affinity for oil, said mass comprisinga plurality of discrete core particles of fibrous material, and powderedcoal bonded to said discrete core particles by fused polyethylene.